Finally some recognition of all the anecdotal weather we’ve been talking about here – Anthony
World Meteorological Organization
Thu Aug 21, 2008 1:15am IST
LONDON (Reuters) – The first half of 2008 was the coolest for at least five years, the World Meteorological Organisation (WMO) said on Wednesday.
The whole year will almost certainly be cooler than recent years, although temperatures remain above the historical average.
Global temperatures vary annually according to natural cycles. For example, they are driven by shifting ocean currents, and dips do not undermine the case that man-made greenhouse gas emissions are causing long-term global warming, climate scientists say.
Chillier weather this year is partly because of a global weather pattern called La Nina that follows a periodic warming effect called El Nino.
“We can expect with high probability this year will be cooler than the previous five years,” said Omar Baddour, responsible for climate data and monitoring at the WMO.
“Definitely the La Nina should have had an effect, how much we cannot say.”
“Up to July 2008, this year has been cooler than the previous five years at least. It still looks like it’s warmer than average,” added Baddour.
The global mean temperature to end-July was 0.28 degrees Celsius above the 1961-1990 average, the UK-based MetOffice Hadley Centre for climate change research said on Wednesday. That would make the first half of 2008 the coolest since 2000.
“Of course at the beginning of the year there was La Nina, and that would have had the effect of suppressing temperatures somewhat as well,” Met Office meteorologist John Hammond said.
Dear Mike Bryant,
Thank you for your response. I will read physorg.com.
In India you will see more news and information supporting global warming as a fact – at the same time, you will see them admitting that India cannot progress without increased use of oil. This contradiction is obvious if you watch government controlled TV. That is one reason Indian government wanted to get an agreement on the nuclear deal with U.S. – but the Marxist party (they are strong to create trouble – but not strong enough to initiate new policies) is against any such deals because of their dislike to US – and their strange liking to Russia and China. Compter related industries are growing so fast here – but not enough power, so if you walk at night in the business area in Bangalore – you will hear this humming sound from the basement of almost every tall building since each one has their own separate generators.
Population in general believe there is warming – or at least change in weather patterns. In Kerala (Trivandrum) we felt hotter year after year – and Monsoons are not regular – not enough rain – so people believe in some form of warming. But there are few skeptics also. Dr. Arun D. Ahluwalia is one of them – just google him. If you contact him may be you can find more specific information on the strength of skeptical associations – http://arundeep.ahluwalia.googlepages.com/cvarunahluwalia,professorofgeology
It would be good to invite him to join the blogg.
If there is a large skeptical Indian community it will be outside India.
I don’t know what to believe about global warming. That is why I read this blog – because I read interesting articles and interpretations I do not always find in India. Most educated people are the same way – I think. Most of them do believe in warming to a degree – but most of them take IPCC, NOAA, etc on its face value.
There is no special way to address Indians. In general Indians are very respectful to older people (even one or two years older) – on the other hand you see some physical fights and name callings in Parliaments between opposing party members – which I assume you don’t have in U.S. Jeez is right – I do not know of particular cultural norms. From the movies I understand Americans are very direct. But most Indians are not direct – they may not say ‘no’, they will say ‘it is difficult to do’.
Hi John,
You wrote: “Just because a study is continuous does not mean the results are correct or reliable. I do not trust conclusions based on satellite data, unless it is verified and re-verified by other teams.”
There are two points here.
First is the advantage of continuous long term data sets over spot results. If you check Hanna et al. (2007) “Greenland Ice Sheet Mass Balance” you will read the statement: “Most of the observational studies have data spans of less than a decade, which also means that the interpretation of their results may be seriously affected by large year-to-year variability in GrlS mass turnover, e.g. sudden glacier accelerations. Since the Helheim and Kangerdlugsuaq glaciershave been shown to accelerate and decelerate over just a few years, these ‘speed-ups’ may just represent flow variability on interannual time scales and therefore represent the ‘weather’ rather than the ‘climate’ of the GrlS.” In another section Hanna et al. talk about the other cause of large interannual variability: “Recent high snow accumulation events occurred in winter 2004/05, concentrated in West Greenland, and 2002/03 in SE Greenland. On the other hand, 2006 was the sixth lowest precipitation year in the 49-year ECMWF Greenland record, which together with the high 2006 runoff, resulted in the second-lowest annual ice sheet net mass input since 1958.”
This confirms that continuous data spans over a decade are more reliable than spot results for determining long term trends, due to these two strongly interannually variable factors.
In your second point you state that you “do not trust conclusions based on [365 days/year 24/7] satellite data”, unless they are verified.
Satellite altimetry has its limits, I am sure. It is obviously much more reliable for measuring a static solid surface such as the top of a glacier than measuring something as variable as a heavily heaving ocean, particularly when the deck of a metal ship can distort the reading for several square miles. It cannot differentiate well between light snow, heavily compacted snow firn or ice, so these density differences must be accounted for when converting altitude change to mass balance. It is not too good where there are steep contours, so alternate methods must be used to supplement satellite data along steep coastal regions. It is worthless outside the range of satellites (ex. near the poles), so other methods must be used to calculated changes there.
As you will see, these weaknesses have been addressed and the results verified by other means.
You wrote, “area itself is not important, one can focus on a small area with higher activities and neglect vast other areas with relatively small level of activities, and could get better results than covering the whole area. These are complicated issues, and I am happy to leave them to the experts to decide.”
In any study, there are two things that are important: the scope/extent of the study and the time frame covered. Spot studies of limited areas are nice as backup information for those limited areas over a piece of the time frame. Many such spot studies have been made for the easily accessible coastal areas of both the AIS and GIS, where there is by definition more ice loss than in the interior. These have been used to project the demise of both ice sheets, essentially ignoring the vast interior area.
Johannessen (GIS) and Wingham (AIS) were the first to use long range continuous satellite measurements to show that these vast interior areas were actually growing significantly in mass, due to increased snowfall, thereby challenging the previously assumed paradigm of mass balance in the interior.
Wingham (AIS) went so far to convert the readings to a mass balance and add in estimates for the areas not measurable by satellite (a 6% marginal coastal region, where contours are too steep for a good reading and a 22% interior region, which lies too close to the pole and is therefore outside the satellite range). Wingham concluded overall AIS growth over the period 1993-2003.
Johannessen (GIS) did not go this far, but in a subsequent study by Zwally the Johannessen satellite readings were converted to a mass balance; in addition, the marginal coastal areas not captured by Johannessen were added in (3% by adding in ATM airborne readings near the coast and a further 7% by “optimum interpretation”). The only strange deviation is that Zwally truncated a six-month cold period (October 2002 to April 2003) from Johannessen’s record, a period described both by other reports as well as from the detailed Johannessen figures as a period of “high snow accumulation”. Despite this truncation, Zwally conculded overall GIS growth over the period 1993-2003.
IPCC 2007 SPM claimed overall ice mass loss in both AIS and GIS over the period 1993-2003.
There are many other studies out there, some covering a piece of this ice sheet here and another piece there, some covering spot data from one or two summer seasons or covering totally different time frames, some concluding that short-term studies (with data spans of less than one decade) are essentially meaningless due to the large year-to-year variability in mass turnover, etc., but Johannessen/Zwally (GIS) and Wingham (AIS) are the only studies covering both entire ice sheets over the entire period 1993-2003.
Those, John, are the facts in summary again.
From these facts I concluded that IPCC ignored (or rejected or refused to accept as correct) the conclusions of published studies which directly refuted its claim of net ice mass loss in the AIS and GIS over the period 1993-2003.
I am not at all saying that they ignored ALL studies, just the two that covered the two entire ice sheets over exactly the entire same time period of their claim, which both concluded net ice mass gain in both ice sheets over the period 1993-2003.
So let’s lay this discussion to rest with the conclusion that you do not accept my premise even though you have been unable to disprove it. OK?
I believe most reasonable visitors to this site can make up their own minds on this.
So if you are game to continue our discussion, we can move on to sea level.
Regards,
Max
Max, I will get back to you in a day – too many emergency cases.
Max, Why don’t you go ahead and write your opinion on sea levels. I will be tied up for a couple of more days. I cannot control my schedule, unfortunately.
Rama Sundaran Sharma,
Reading your letter makes me realize that as far as AGW is concerned our countries are very much alike. I took your advice and invited Dr. Arun D Ahluwalia to comment here. Here is the email I sent him.
Dr. Arun D Ahluwalia,
My name is Michael Bryant. I am writing this short note to invite you to comment, regularly if you wish, at http://wattsupwiththat.wordpress.com/
This is the blog created by the founder of surface stations.org, Anthony Watts. As I am sure you know, Mr. Watts volunteer organization is documenting the serious deficiencies of the global surface temperature records and surface station conditions that are primarily the responsibility of Dr. James Hansen of Goddard Institute of Space studies, a part of NASA.
Thanks for you consideration of this request,
Michael Bryant
Looking forward to more dispatches from a faraway place,
Mike Bryant
Hi John,
There are some basic problems with the IPCC claims on sea level, which I will list below.
IPCC 2007 SPM claims a faster rate in sea level rise in the period 1993-2003 over earlier periods (pp.5,7). “Global average sea level rose at an average rate of 1.8 [1.3 to 2.3] mm per year over 1961 to 2003. The rate was faster over 1993 to 2003: about 3.1 [2.4 to 3.8] mm per year. Whether the faster rate for 1993 to 2003 reflects decadal variability or an increase in the longer-term trend is unclear.”
http://ipcc-wg1.ucar.edu/wg1/Report/AR4WG1_Print_SPM.pdf
The actual measured record based on tide gauges shows significant up and down swings in rate of change (from positive to negative), but an overall slowing down instead of an acceleration, with the rise in sea level in the second half of the 20th century significantly lower than the rise in the first half.
http://www.agu.org/pubs/crossref/2007/2006GL028492.shtml
This report concludes: “Extending the sea level record back over the entire century suggests that the high variability in the rates of sea level change observed over the past 20 years were not particularly unusual. The rate of sea level change was found to be larger in the early part of last century (2.03 ± 0.35 mm/yr 1904–1953), in comparison with the latter part (1.45 ± 0.34 mm/yr 1954–2003). The highest decadal rate of rise occurred in the decade centred on 1980 (5.31 mm/yr) with the lowest rate of rise occurring in the decade centred on 1964 (−1.49 mm/yr). Over the entire century the mean rate of change was 1.74 ± 0.16 mm/yr.”
Another 2003 study concludes, “In the last 300 years, sea level has been oscillating close to the present with peak rates in the period 1890–1930. Between 1930 and 1950, sea fell. The late 20th century lacks any sign of acceleration.”
http://www.sciencedirect.com/science?_ob=ArticleURL&_udi=B6VF0-49C5G0W-2&_user=10&_rdoc=1&_fmt=&_orig=search&_sort=d&view=c&_acct=C000050221&_version=1&_urlVersion=0&_userid=10&md5=d471cc450145c491b716051f36f61df5
In other words, an acceleration in sea level rise as suggested by IPCC is not supported by the tide gage record.
Prior to 1993 IPCC uses the tide gage record of sea level, which records measurements at several shorelines; in 1993 this was changed to satellite altimetry, which measures the entire ocean. The change in method coincides with an apparent acceleration of sea level rise over previous periods. IPCC throws out the tide gauge record, which shows significant fluctuations but no such acceleration. To compare one set of results using one method covering one scope over one time period (prior to 1993) with another set of results using a different method covering a different scope over another time period (after 1993) and then using this cobbled-together record to claim an acceleration trend between the two time periods is bad science, at best, especially if the record for the latter time period which uses the same method and covers the same scope for both periods and shows no acceleration is ignored.
A more recent study using satellite altimetric data entitled “Decadal Trends in Sea Level Patterns: 1993-2004” concluded that the increase over this period was 1.6 mm/year (or around one-half the rate reported by IPCC and slightly lower than the average for the entire 20th century). It did conclude, however that “systematic errors are likely to dominate most estimates of global average change” and the [satellite] “database is insufficient to compute sea level trends with the accuracy necessary to discuss the impact of global warming”.
http://ocean.mit.edu/~cwunsch/papersonline/Wunschetal_jclimate_2007_published.pdf
Despite the reservations stated above, the impression is given by IPCC that satellite altimetry provides a more accurate methodology for measuring sea level trends than the older tide gages, “These estimates are based on improved satellite and in situ data now available.”
Based on the evaluation of the scientists directly involved in satellite altimetry to measure sea levels, it appears that the above-stated reservations on the accuracy of this method are well founded and the IPCC statement referring to “improved satellite data” is a bit of a stretch.
A report by one of the NOAA scientists directly involved casts serious doubt on the validity of satellite altimetry for measuring sea levels, concluding, ”every few years we learn about mishaps or drifts in the altimeter instruments, errors in the data processing or instabilities in the ancillary data that result in rates of change that easily exceed the formal error estimate, if not the rate estimate itself.” “It seems that the more missions are added to the melting pot, the more uncertain the altimetric sea level change results become.”
http://www.cosis.net/abstracts/EGU04/05276/EGU04-J-05276.pdf
All in all, it appears that IPCC is on very weak ground in its claim of accelerated sea level rise in the period 1993-2003 over earlier periods.
A more correct conclusion would have been, “Observations show large oscillations in the rate of sea level rise, with an underlying trend of -1.74 ± 0.16 mm/yr over the 20th century and a slight reduction in the rate of rise in the latter 20th century as compared to earlier periods. New satellite altimetry measurements promise another source of data, but this methodology is still in its infancy for sea level measurement, and unable to provide accurate trend data today.”
That would have been a true and honest statement.
Regards,
Max
Max, I hope you are still around. Sorry, I have been soooooo busy with my real work and it will possibly stay that way until the end of the year. It got incredibly busy after we started a couple of projects, which turned out to give very encouraging results. I certainly would like to come back and discuss with you, but for the next couple of months I may not be able to do that. Sorry for that. This is the first time I had a chance to come back, just to post a couple of lines. But I hope you will be checking here frequently. Thanks.
John
Max, are you still checking here? If you are, I might address your previous post soon. I might get a break from the busy time.
John
Hullo, John. Hope you’ll be around again when you have more time. It’s hard for anyone to spot a post this far back, though. “Off the first page syndrome”, and all.
Hi Evan,
Yes, I know no one will come this far back. But I was trying to catch Max, I had to quit at the middle of the discussion at that time, and I thought Max had some excellent points to make, but I knew I did not have enough time to go through them carefully and read the literature to make any meaningful comments;. I have not kept up with the posts, have you seen him around recently?
Hope everything is well with you.
Hmm. Now you mention it, I don’t recall seeing him about lately. (The only reason I caught it was while moderating.)
Things may be looking up for me at last, though I can’t get into details. Also, I – may – be able to land a teaching job for NYC, if I’m a Good Person and promise to take a lot of harmful so-called “education” courses. Hope things are well with you, and happy Thanksgiving.
It is too bad that he is gone…..I was hoping to continue the discussion.
So wonderful to hear about your academic job prospects, that is so nice. I will keep my fingers crossed. I am sure you will enjoy academics very much, especially with your various skills we have seen in this site. Congratulations, good luck and wish you all the best. In fact, I sincerely hope you will be able use the academic position to help to shore up arguments against AGW – that would certainly be a great contribution.
Life has been extremely busy – we have a clinical study going on, teaching two graduate courses, and no relaxation. Finally the semester is almost over, and Christmas is coming.
Happy Thanksgiving!!